The invention relates generally to indexable cutting inserts and associated material removal tools. More specifically, the invention concerns indexable polygonal inserts for face milling or shallow boring of square or perpendicular shoulders in workpiece material.
Traditionally, to machine a square, or 90xc2x0 corner, the cutting tool used either employed a helical cutting edge or a neutral linear cutting edgexe2x80x94i.e. an edge exhibiting zero axial rake. However, the neutral cutting edge approach has presented clearance problems in the past with other portions of the cutting insert used with the tool.
Hence, there is seen to be a need in the cutting tool art for providing an indexable insert adaptable for mounting in a cutting tool, such as a face mill or shallow boring bar, which can be oriented to yield an active cutting edge exhibiting zero axial rake, yet capable of providing protection to a trailing cutting edge of the insert.
Accordingly, in one aspect of the invention, an indexable cutting insert comprises a polygonal body having substantially parallel major surfaces joined by peripheral side surfaces substantially perpendicular to the major surfaces to form corners of the polygon, a main cutting edge extending in a first direction from each corner in a downward direction relative to a major surface associated with the corner, and a wiping edge spaced from the corner in a second direction and lying substantially in the plane of the major surface.
In another aspect of the invention, a rotatable material removal tool has at least one negative geometry insert mounted thereto for forming a shoulder in a workpiece as the tool is rotated, each insert positioned in a pocket of the tool so as to provide negative axial and negative radial rake, but with an active cutting edge of each insert extending in a first direction from a corner of the insert substantially parallel to an axis of rotation of the tool and with a wiping edge extending in a second direction away from the corner of the insert, whereby a substantially 90xc2x0 shoulder is formed in a workpiece subjected to the rotating tool""s cutting action.